Data Points

Data sources can return data for one or more performance metrics. Each metric retrieved by a data source is represented by a data point.

You can define data points to data sources with all source types except SNMP and VMware. Because these data source types each rely on a single data point for performance metrics, additional data point definition is not needed.

To add a data point to a data source:

  1. From the Navigation menu, select Advanced > Monitoring Templates.
  2. In the Data Sources area, highlight the row containing a data source.
  3. Select Add Data Point from the Action menu. The Add Data Point dialog box appears.
  4. Enter a name for the data point, and then click Submit.
  5. Double-click the newly added data point to edit it. Enter information or make selections to define the data point:
    • Name- Displays the name you entered in the Add a New DataPoint dialog.

    • RRD Type- Specify the RRD data source type to use for storing data for this data point. Available options are:

      • COUNTER- Saves the rate of change of the value over a step period. This assumes that the value is always increasing (the difference between the current and the previous value is greater than 0). Traffic counters on a router are an ideal candidate for using COUNTER.

      • GAUGE- Does not save the rate of change, but saves the actual value. There are no divisions or calculations. To see memory consumption in a server, for example, you might want to select this value.

      • DERIVE- Same as COUNTER, but additionally allows negative values. If you want to see the rate of change in free disk space on your server, for example, then you might want to select this value.

      • ABSOLUTE- Saves the rate of change, but assumes that the previous value is set to 0. The difference between the current and the previous value is always equal to the current value. Thus, ABSOLUTE stores the current value, divided by the step interval.

    • Create Command- Enter an RRD expression used to create the database for this data point. If you do not enter a value, then the system uses a default applicable to most situations.

    • RRD Minimum- Enter a value. Any value received that is less than this number is ignored.

    • RRD Maximum- Enter a value. Any value received that is greater than this number is ignored.

  6. Click Save to save the defined data point.